The invention relates to a package structure, and in particular to an exposed pad module integrating a passive device therein.
Due to the demand for high-frequency, high-speed system-in-package (SIP), small-aspect package design capable of effective heat dissipation and excellent electrical performance is necessary. Thus, package technology is a critical issue in SIP design. QFN (quad flat no-lead), capable of low pin inductance, is a widely anticipated technology, which utilizes a lead frame as a substrate.
A lead frame for QFN has a die paddle, attaching a chip thereto, and a plurality of leads beyond the die paddle. The chip has a plurality of terminals respectively electrically connecting the corresponding leads. An encapsulant covers the chip and respectively exposes the ends of the leads. The lead ends and the encapsulant are approximately coplanar, achieving a QFN package.
A QFN-package has smaller aspect and better electrical performance than other package types. In a printed circuit board assembly (PBCA) process, QFN packages and passive devices are individually disposed on a PCB, resulting in the necessity to design PCB wirings to electrically connect corresponding QFN packages and passive devices. The required wirings may enlarge the PCB and/or wiring density thereof. Denser PCB wirings may cause crosstalk therebetween.